From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 5486D13838B for ; Tue, 31 Mar 2015 09:36:29 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 85A0EE0ADA; Tue, 31 Mar 2015 09:36:23 +0000 (UTC) Received: from mail-la0-f47.google.com (mail-la0-f47.google.com [209.85.215.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 3583EE0A97 for ; Tue, 31 Mar 2015 09:36:22 +0000 (UTC) Received: by lajy8 with SMTP id y8so8244811laj.0 for ; Tue, 31 Mar 2015 02:36:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=toJ/+dwOqMGAPCFIDPzmAyKMdDQ0tHiD23wMIv0d+tc=; b=Xroze/SCGMbnS1QlozbYoVcNqsYp64DCH3ruSmyoG5OcFs09DreA4a+ACG27s8ib3A o1sZZBB8xwFUeKyimNKFO1X+wDMn7YkhAqmrAWCl1zOPVmPS5fsL8LGtUmL93E6JVaq4 hjL6IVdhNnrPQaabCI3ZAXg7DhHZxQFDcyUZZaoLrb5j3BtD9oWuTATm/aQaXFX1goGp GXAnmIgp8CHGVRMuLjpF0/aWaGx324pVLY+ltNk9wPxZYmP3gL3XBo9uhycUhXU93Nvo RLR/wnUFwMN2VobcVFuHJUPhTraBDAIVSGizL5ZTzZ0OvSnwoxI+zYe3LOQjuFpdCc7E fVVQ== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.152.87.115 with SMTP id w19mr30487681laz.66.1427794580862; Tue, 31 Mar 2015 02:36:20 -0700 (PDT) Received: by 10.152.109.230 with HTTP; Tue, 31 Mar 2015 02:36:20 -0700 (PDT) In-Reply-To: <1887274.L0doMiab5F@navi> References: <20150321152656.a82a84b3e8a32c8b68554548@gmail.com> <20150322155852.GA1081@ca.inter.net> <87pp7sqf0b.fsf@heimdali.yagibdah.de> <1887274.L0doMiab5F@navi> Date: Tue, 31 Mar 2015 05:36:20 -0400 Message-ID: Subject: Re: [gentoo-user] Re: How to poweroff the system from user? From: Tom H To: Gentoo User Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 20514338-0d0a-42a3-963e-e0648792785a X-Archives-Hash: a9ef73516ed1925807874f911986d557 On Tue, Mar 31, 2015 at 1:57 AM, Fernando Rodriguez wrote: > On Linux now there's the Magic SysRq Key feature for that. If enabled (I think > it is by default, may be wrong) you can use ctrl-alt-sysrq plus one these keys > even if your kernel panics or freezes in most cases (ctrl may only be needed > from xorg): > > r - to get the keyboard back so you can switch to VT if xorg freezes > e - to terminate all processes gracefully (SIGTERM) except pid 1 > i - to terminate all processes forcefully (SIGKILL) except pid 1 > s - to sync all filesystems > u - to unmount them and remount readonly > b - to reboot You have to set "MAGIC_SYSRQ" to "y" for it to be enabled. You can set the "capabilities" of sysrq either via 'MAGIC_SYSRQ_DEFAULT_ENABLE" or via sysctl. Debian uses the former (to set it to 438) and Ubuntu and Fedora use the latter (to set it to 176 and 16 respectively). "16" is systemd upstream's default whereby you can only sync filesystems. It's the kind of value that can be the source of a lot of arguing... > Easy to remember as "Reboot Even If System Utterly Broken" I remember it as the reverse of "busier".